The present invention relates to transaction printers and, more particularly, to an improved sales receipt printing mechanism for a transaction printer.
In the art of transaction printers, it is customary for the drive mechanism to comprise two motors. One of the two motors is used for driving the supply roll during the printing operation. The second of the two motors is used to operate a cutting blade for severing the advanced paper web, once the receipt is printed.
The present invention seeks to provide a single drive motor to accomplish both the paper feed, and the paper cutting operation. The reduction of parts minimizes the cost of the printing mechanism, while providing a more compact printing unit.
The current invention provides a single, bi-directional stepper motor connected to the paper feed rollers in a receipt printer. The stepper motor is programmed to turn the paper feed rollers, when operative in a clockwise direction. The motor is also connected to the pinion gear of a rotating knife blade that causes the severance of the paper, when operative in a counter-clockwise direction.
The motor is connected to the knife blade pinion gear through a spring-wrapped, one-way clutch. The one-way clutch is intermediate of the pinion gear, so that when the motor is operative in a clockwise direction, as when it is driving the paper feed rollers, it does not cut the receipt.
The stepper motor is programmed to make two initial steps to drive the paper feed rollers before printing is initiated. This is necessary to eliminate squeezing together or compressing the print dots on the first row of the receipt printout during the print start-up. The extra two motor steps is accomplished through the print software.
In accordance with the present invention, there is provided an improved transaction printer drive mechanism. The drive mechanism comprises a single, bi-directional stepper motor connected to the paper feed rollers driving the receipt paper web. The stepper motor is programmed to turn the paper feed rollers, when operative in a clockwise direction. The motor, when operative in a counter-clockwise direction, causes the severance of the receipt paper web. This is accomplished by its connection to the pinion gear of a rotating knife blade. The motor is connected to the knife blade pinion gear through a spring-wrapped, one-way clutch. The one-way clutch is intermediate of the pinion gear, so that when the motor is operative in a clockwise direction, as when it is driving the paper feed rollers, it does not cut the receipt. The stepper motor is programmed to make two initial steps to drive the paper feed rollers before printing is initiated. This is necessary to eliminate squeezing together the print dots on the first row of the receipt printout during print start-up.
It is an object of this invention to provide an improved drive mechanism for a transaction printer.
It is another object of the invention to provide a sales receipt printing and severing mechanism that is operative through a single, bi-directional motor.
It is still another object of this invention to provide an improved drive mechanism for a transaction printer that is less expensive and more compact.